Coordination of full actuated traffic controllers

ABSTRACT

There is disclosed a coordination unit for coordinating the operation of a full actuated traffic controller in an interconnected signalized system. The controller serves to control a traffic signal which displays go, caution, and stop intervals to at least two traffic phases each having associated therewith traffic detector means for detecting traffic in that phase and developing a go interval initiating control signal in response to the detection of traffic and developing a go interval terminating control signal in the other phase or phases. Also, the controller includes control circuit means associated with each phase and comprising, go interval actuation means associated with each phase for commencing a go interval display to the associated phase, and go interval terminating means for terminating the go interval displayed upon removal of a said signal from the control circuit means. The coordination unit comprises means for cyclically timing successive background cycles having each a predetermined time duration; means for dividing the background cycle into at least two background-cycle time intervals respectively associated with each of the phases; actuatable means responsive during one of the associated intervals for coupling one of the traffic detector means to an associated one of the control circuit means for the duration of the associated interval so that a control signal developed by the traffic detector means is applied to the control circuit means only during that interval; and, actuatable means responsive during the other associated interval for coupling the other traffic detector means to the associated control circuit means so that a said control signal developed by the other traffic detector means is applied to the other control circuit means only during the other associated interval.

Waited States Patent [72] Inventor Ralph M. Riddle, Jr.

Moline, Ill. [21] Appl. No. 814,407 [22] Filed Apr. 8, 1969 [45]Patented Nov. 2, 1971 [73] Assignee Gulf & Western Industries New York,N .Y.

[54] COORDINATION OF FULL ACTUATED TRAFFIC CONTROLLERS 11 Claims, 6Drawing Figs.

[52] ILLS. Cl 340/35 [51] Int. Cl G08g 1/08 [50] Field of Search 340/35,37, 40, 41

[56] References Cited UNITED STATES PATENTS 3,500,308 3/1970 Riddle, Jr.et al 340/35 Primary Examiner- Kathleen H. Clafi'y AssistantExaminer-Randall P. Myers Att0rneyMeyer, Tilberry and Body ABSTRACT:There is disclosed a coordination unit for coordinating the operation ofa full actuated traffic controller in an interconnected signalizedsystem. The controller serves to control a traffic signal which displaysgo, caution, and stop intervals to at least two traffic phases eachhaving associated therewith traffic detector means for detecting trafficin that phase and developing a go interval initiating control signal inresponse to the detection of traffic and developing a go intervalterminating control signal in the other phase or phases. Also, thecontroller includes control circuit means associated with each phase andcomprising, go interval actuation means associated with each phase forcommencing a go interval display to the associated phase, and gointerval terminating means for terminating the go interval displayedupon removal ofa said signal from the control circuit means. Thecoordination unit comprises means for cyclically timing successivebackground cycles having each a predetermined time duration; means fordividing the background cycle into at least two background-cycle timeintervals respectively associated with each of the phases; actuatablemeans responsive during one of the associated intervals for coupling oneof the traffic detector means to an associated one of the controlcircuit means for the duration of the associated interval so that acontrol signal developed by the traffic detector means is applied to thecontrol circuit means only during that interval; and, actuatable meansresponsive during the other associated interval for coupling the othertraffic detector means to the associated control circuit means so that asaid control signal developed by the other traffic detector means isapplied to the other control circuit means only during the otherassociated interval.

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CAM SWITCH HEZEEE qa CAM SWITC H 2 CAM SWITCH 3 CAM SWITCH 4 CAM SWITCH8 CAM SWITCH 9 ATTORNEYS COORDINATION OF lFUlLlL ACTUATIEID TRAlFlFlCCONTROLLERS This invention pertains to the art of traffic control and,more particularly, to apparatus and method for coordinating theoperation of full-actuated local traffic controllers in aninterconnected, progressive, signalized system.

This invention is particularly applicable to two-phase, fullactuatedlocal traffic controllers, and will be described with particularreference thereto, although it will be appreciated that the inventionhas broader applications and may be employed with any two or more phase,full-actuated or semiactuated local controller.

A full-actuated local traffic controller has associated therewithtraffic actuatable detectors for each traffic phase, i.e., movement,being controlled. Thus, a three-phase, full-actuated traffic controller,for controlling traffic flow through an intersection of three trafiicphases, has associated therewith at least one detector for each phasefor detecting traffic, i.e., vehicles in that phase, and registeringtraffic demand with the controller. The controller serves to allocateright-of-way intervals by means of a signal light located at theintersection to each of the phases in accordance with traffic demand. Asemiactuated traffic controller is similar to a full-actuated trafliccontroller, but at least one phase is a nonactuatable phase; that is,there is no detector associated with that phase. The nonactuatablephase, usually reserved for phases having heavy traffic flow, such asmain street, is allocated a minimum fixed time right-of-way interval bythe controller during each cycle of operation, with right-of-wayintervals being allocated to the actuatable phases dependent on trafficdemand. Thus, a fullactuated traffic controller allocates right-of-wayintervals in a more efficient manner than a semiactuated controller,since the latter must allocate a minimum right-ofway interval to thenonactuatable phase during each cycle of operation whether there istraffic demand on that phase or not.

Frequently, municipalities require that all of the local controllers atvarious street intersections, whether the controllers be full-actuated,semiactuated or pretimed controllers, be interconnected in a coordinatedsignal system supervised by a master controller. The purpose ofcoordinated operation of local intersection controllers is to obtain asmooth progression of traffic within the signal system. ln such acoordinated signal system, the maximum time length of the traffic signalcycle of each of the interconnected local controllers is determined bythe time length of a background cycle established by a mastercontroller. The background cycle may in turn be determined by a pretimedor programmed schedule, or on the basis of varying traffic demands, asregistered with the master controller by vehicle detectors located atvarious locations in the signal system.

Heretofore, coordination of actuated local controllers has been directedto coordination of semiactuated local controllers, or full-actuatedlocal controllers, which for purposes of coordination have beenconverted to semiactuated local controllers, with the end result beingto allocate a fixed minimum amount of right-of-way time to main streettraffic flow to facilitate traffic flow through the intersections alongthe main street. Both semiactuated and full-actuated traffic controllersnormally include maximum time-out circuits for the actuatable phase, orphases, which serve upon the completion of predetermined time toterminate allocation of a right-of-way interval to the actuatable phase,whereupon a timed caution interval is allotted to that phase, afterwhich that phase is denied right-of-way movement during that cycle.

Coordination of such actuated controllers is accomplished with acoordination unit associated with each controller. Such a coordinationunit determines the proper time for releasing the controller to endallocation of a right-of-way interval to the nonactuatable phase afteran actuation has occurred on an actuatable phase, and for forcing thecontroller to terminate allocation of a right-of-way interval to anactuatable phase and commence allocation of a right-of-way interval tothe nonactuatable phase. In order to maintain efficient traffic flowwithin the signalized system, the point in time, during the masterdetermined background cycle, that the right-of-way interval of anonactuatable phase is terminated, must be accomplished at the propersplit of the cycle as determined by the master controller. The mastercontroller, which may be traffic adjusted, serves to determine the mostefficient traffic cycle duration, the best division of the cycle betweenmain street and cross street traffic, and the most effective offset ofthe start of the cycle at each succeeding intersection. After theseparameters are determined they are imposed on each interconnected localcontroller in the coordinated signal system by means of the coordinationunits.

Coordination units known heretofore for coordinating the operation ofactuated local controllers generally include a motor driven wheel, knownas a coordination dial, carrying a plurality of switch actuatingelements, known as keys. The time cycle length to complete onerevolution of the coordination dial corresponds with the time length ofthe background cycle determined by the supervising master controller.One revolution of the coordination dial times one complete trafficsignal cycle for the associated traffic controller. One of the keys,known as the release key, is placed at or near the zero point or releasepoint of the coordination dial, and serves to initiate termination ofallocation of a right-of-way interval to the nonactuatable phase afteran actuation has occurred on an actuatable phase. A second key, spaced apredetermined angular distance from the release key, and known as asplit key or maximum time out key, serves to initiate termination ofallocation of a right-of-way interval to an actuatable phase if aright-of-way interval has not been previously terminated by lack ofdetector actuations. The release key serves once during each revolutionof the coordination dial to actuate a switch which connects a source ofpower to a timing circuit in the controller associated with thenonactuatable phase, such as to the plate circuit of a vacuum tube in anRC timing circuit or to a step switch driver coil. This causes thetiming circuit for the nonactuatable phase to terminate its timingfunction and thereby terminate allocation of a righ't-of-way interval tothe nonactuatable phase, whereupon the controller then normally times acaution clearance interval for the nonactuatable phase, after whichright-of-way movement is denied to the nonactuatable phase during thatcycle. Similarly, the maximum time-out key, or split key, serves onceduring each revolution of the coordination dial to actuate a secondswitch which serves to connect a source of power to a second timingcircuit in the controller associated with the actuatable phase. Thiscauses the timing circuit to terminate its timing function, whereuponallocation of a right-of-way interval to the actuatable phase isterminated, which is normally followed by a timed clearance interval,after which right-of-way denied to the acutatable phase.

The purpose of such a coordination unit as described above is toallocate during the background cycle a fixed minimum amount ofright-of-way time to the main street, or nonactuatable phase, tofacilitate traffic flow along the main street through the variousintersections. Accordingly, the time lapse during the background cyclefrom the point in time at which the maximum time out or split keyactuates the switch associated with the actuatable phase, to the pointin time at which the release key actuates the switch associated with thenonactuatable phase, is the guaranteed period of time during thebackground cycle that a right-of-way interval is allocated to mainstreet traffic flow. The time lapse from the point in time at which therelease key actuates the switch associated with the nonactuatable phase,and the point in time at which the maximum time out or split keyactuates the switch associated with the actuatable phase, is thepotential period of time during the background cycle that a right-of-wayinterval may be allocated to cross street tramc flow. The vehicledetector associated with the actuatable phase must be actuated prior tothe release point in the background cycle before a right-of-way intervalcan be actually allocated to the actuatable phase. If the vehicledetection on the actuatable phase occurs at a point in time just afterthe release point in the background cycle, the actuatable phase will bedenied rightof-way movement until the next cycle of operation, orsubstantially the entire time period of the background cycle which, forexample, may be on the order of 120 seconds. A further disadvantage ofprevious methods of coordinating the operation of semiactuatedcontrollers or full-actuated controllers, which have been converted tosemiactuated controllers for coordination purposes, is that when crossstreet traffic flow is heavy and main street traffic flow is light,trafiic on the cross street must be denied right-of-way movement whilethe guaranteed right-of-way interval is allocated to the main streetalthough there may be little or no traffic demand on the main street.

Coordination of full-actuated local controllers has heretofore includeda traffic controller which serves to control a traffic signal fordisplaying go, caution and stop intervals to at least two trafficactuatable phases, each having associated therewith vehicle actuatabledetector means for registering traffic demand with the controller. Inaddition, the operation of the full-actuated traffic controllers iscoordinated by a coordination unit having a background cycle in which apredetermined point on the cycle was selected for guaranteeing when eachactuatable phase controlled by the full actuated controller is requiredto yield to another actuatable phase in accordance with traffic demand.One such coordination system is described in US. Pat. No. 3,350,308,issued Mar. 10, I970 upon application Ser. No. 552,328, entitled COOR-DINATION OF FULL-ACTUATED TRAFFIC CONTROL- LERS, filed May 23, 1966, andassigned to the assignee of the present invention.

The present invention is directed toward coordination of full-actuatedtraffic controllers, but contrary to previous methods of coordination,the present coordination unit provides termination of a go intervaldisplay by preventing signals that are developed by a traffic detectorfrom being applied to the detector input terminals of the trafficcontroller.

In accordance with one aspect of the present invention, the operation ofactuated traffic controllers is coordinated by a background cycle havinga first time interval for coupling the traffic detectors associated withone phase to the traffic controller, and a second interval for couplingthe other traffic detectors associated with the other traffic phase tothe traffic controller to thereby provide coordination of actuatedtraffic controllers.

In accordance with a more limited aspect of the present invention,apparatus and method are provided for dividing the background cycle intoat least two timed intervals respectively associated with each of thephases, and actuatable means responsive during one of the intervals forcoupling one of the traffic detectors to the traffic controller for theduration of that interval so that a signal developed by the trafiicdetectors is applied to the traffic controller only during thatinterval, and actuatable means responsive during the other interval forcoupling the other traffic detector to the traffic controller for theduration of that interval so that a said signal developed by the othertraffic detector is applied to the traffic controller only during thatinterval.

In accordance with a more limited aspect of the present invention, thebackground cycle is divided so that each phase includes a secondinterval which commences substantially upon termination of the firstinterval; and, the coordination unit includes for each phase, actuatablememory means for receiving and storing a control signal during thesecond interval and for applying a signal, representative of the storedcontrol signal, to the traffic controller upon termination of the secondInterval.

The primary object of the present invention is to provide coordinationof the operation of a full-actuated local controller controller so thatthe controller operates full-actuated during coordination.

Another object of the present invention is to coordinate the operationof a full-actuated local controller so that signals are applied to thecontroller by the traffic detectors only during a preselected intervalof a background cycle.

A still further object of the present invention is to coordinate theoperation of a full-actuated local controller so that during thebackground cycle, the controller allocates go signal display time to thefullest extent in accordance with traffic demands.

These and other objects and advantages of the invention will becomeapparent from the following description of the preferred embodiment ofthe invention as read in conjunction with the accompanying drawings inwhich:

FIG. 1 is a block diagram illustrating a pair of coordinated, two-phase,full-actuated local traffic controllers, a master controller, andassociated coordination units in accordance with the present invention;

FIGS. 2 and 2A are a block diagram, schematic illustration, split alonglines A-B and A'-B, illustrating a coordination unit, in accordance withthe present invention, connected to a master controller and to atwo-phase, full-actuated local traffic controller;

FIG. 3 is a schematic diagram illustrating the preferred embodiment ofthe coordination unit;

FIG. 4 is a schematic diagram of one of the coordination dials of thecoordination unit; and,

FIG. 5 is a graphical chart illustrating the intervals of operation.

GENERAL DESCRIPTION Referring now to the drawings, wherein the showingsare for the purposes of illustrating the preferred embodiment of theinvention only, and not for purposes of limiting same, FIG. 1 generallyillustrates a pair of two-phase, full-actuated local controllers LC-land LC2 interconnected through coordination units C-1 and C-2,respectively, with a master controller MC in an interconnected,progressive, coordinated, signalized system. Local controller LC-lcontrols traffic flow through an intersection of trafiic movements, orphases A and B in accordance with the trafiic demand registered with thecontroller by vehicle actuatable detector D-1 and D-3 for phase B, anddetectors D2 and 0-4 for phase A. Right-of-way, clearance, and stopsignals are displayed to phases A and B by a traffic signal device S-lconnected to the controlled by local controller LC-l. Similarly, localcontroller LC-Z controls traffic flow through an intersection of trafficmovements, or phases, A and C in accordance with the traffic demand asregistered with the controller by vehicle actuatable detectors D-5 andD-7 for phase C, and detectors D-6 and D-8 for phase A. Right-of-way,clearance, and stop signals are displayed to phases A and C by means ofa traffic signal device S-2 connected to and controlled by localcontroller LC-Z.

Reference is now made to FIGS. 2 and 2A which generally illustrate amaster controller MC connected to a local controller LC-l through acoordination unit C-l. Coordination unit C-l, takes the form of a threedial coordination unit, similar to that known heretofore, forcoordinating semiactuated traffic controllers, and includes threesynchronous motor driven coordination dials CD-l, CD-2 and CD-3, whichare separately energized to rotate at different speeds and timedifferent background cycles. Each coordination dial carries a pluralityof keys P-l, P-2, P-3, P-8, P-9, P-10, P-ll, P-IS and G extendingradially outward from the dial. In the preferred embodiment, each dialis provided with one hundred equally spaced, longitudinal slotsextending around the circumferential surface of the dial so that thekeys may be spaced from each other in percentages of the backgroundcycle. The keys carried by each dial serve to actuate suitable switches,generally designated as SW in FIGS. 2A and 3.

MASTER CONTROLLER Master controller MC is preferably a pretimed ortraffic actuated controller; however, it is to be appreciated thatvarious other master controllers may be employed with the presentinvention. In order to simplify the explanation of the invention, mastercontroller MC has been greatly simplified and includes threesynchronization cam wheels 10, I2 and 114, each being respectivelydriven by synchronous motors I6, 10 and 20, through suitable gearing, sothat when energized, cam wheels I0, 12 and I4 rotate at differentspeeds. As illustrated, motor 16 is connected across an energizingvoltage source V, and motors I and 20 are connected across voltagesource V by means of normally open coordination dial selector switchesDS-2 and 138-3. With switches DS-2 and DS-3 in their normally openposition, coordination dial CD-l is energized by voltage source V. Uponclosure of dial selector switch DS-2, circuitry within coordination unitC-l is energized to thereby energize only coordination dial CD-2.Further, upon closure of dial selector switch DS-3, circuitry withincoordination unit C-l is energized to thereby energize only coordinationdial CD-3. With reference to FIG. 2, a movable switch contact 22 rideson the peripheral surface of an associated synchronization cam wheel l0,12 or 14, and in the normal condition, is electrically connected with astationary contact 24 for purposes of connecting voltage source V withoffset selector switches 0-1, 0-2 and 0-3 within master controller MC.Switches tl-ll, 0-2 and 0-3, are connected to coordination unit C-ll sothat when one of the offset selector switches 0-1, 0-2 or 0-3 is closed,the switch serves to select the particular offset in effect in theprogressive, coordinated, signalized system. An arcuate slot 26 isprovided in the peripheral surface of each synchronization wheel 10, 12and 14. Once during each revolution of a synchronization wheel, theassociated movable contact rides off of the peripheral surface of thewheel and falls into the arcuate slot 26, thereby breaking electricalcontact with the associated stationary contact 24. This electrical breakextends for approximately 3 percent of the revolution and, is used forsynchronization purposes.

Coordination unit C-ll may be employed to coordinate the operation ofany two or more phase, semiactuated or full-actuated traffic controllersand may, for example, take the form of two interconnected phase units,each being constructed in accordance with the units disclosed anddescribed in U.S. Pat. application Ser. No. 463,449, entitled TRAFFICCONTROL UNIT AND SYSTEM, filed May 2 l, 1965, and assigned to the sameassignee as the present invention. Another type of traffic controllerwhich may be coordinated with coordination unit C-l is the trafficcontroller disclosed and described in U.S. Pat. applications, Ser. Nos.812,476 and 812,480 respectively entitled MULTIPHASE TRAFFIC CONTROLSYSTEM and APPARATUS FOR ALLOCATING AND TIMING A PLU- RALITY OF LOADINTERVALS, and both filed on Aug. 20, 1969. In order to simplify thedescription of the resent invention, only those circuits of localtraffic controller LC-l which are necessary for an understanding of thepresent invention, have been illustrated. With reference to FIG. 2A,local controller LC-l is preferably comprised of a phase A go intervaltermination circuit 30 which includes a phase B detector memory circuitE-l and a normally open relay CRT coupled through a phase A sequencercircuit 32 to a phase A signal circuit S-l. Similarly, local controllerLC-ll includes a phase B go interval termination circuit 34 having aphase A detector memory circuit E-2 and a normally open relay CRBcoupled through a phase B sequencer circuit 36 to the phase B signalcircuit -2. Sequencer circuits 32 and 36 take the form of variouscircuits for sequencing signal circuits 8-11 and 8-2, respectively, andmay take the form of an electromechanical step switch a right counter, asolid-state load sequencer, such as the sequencer disclosed anddescribed in Patent Applications Ser. Nos. 682,814 and 748,583,respectively entitled LOAD SEOUENCER CONTROLLER and SOLID-STATE STEPSWITCH, filed on Nov. 14, l967 and 'July 10, 1968, respectively, andassigned to the same assignee as the present invention. Moreparticularly, normally open relay CRT includes a relay coil CRT-C havingone terminal connected to ground and the other terminal thereofconnected through a normally open switch 33, contacts 37 of a phase Adetector circuit 0-1, and detector memory circuit E-I to the phase Bdetector input terminal of traffic controller LC-ll. For purposes ofsimplification, normally open switch 33 serves the function of couplingdetector memory circuit 15-1 to relay CRT for so long as the phase Aright-of-way signals are displayed by traffic signal circuit S-1, andcontacts 37 of the phase A detector circuit serve the function ofpreventing actuations of the phase A sequencer 32 for so long as signalsare applied to phase detector circuit G-l.. The normally open contactsCRT-ll of relay CRT are connected between one terminal of the coil 30 ofsequencer 32 and ground, and the other terminal of coil 30 is connectedto a voltage supply source V. The output terminals of sequencer 32 arecoupled to the phase A signal circuit S-l. Similarly, the normally openrelay CRV includes a coil CRV-C having one terminal connected directlyto ground and the other terminal thereof connected through a normallyopen switch 39, contacts 41 of a phase B detector circuit G-2, and thephase A detector memory circuit E-2 to the phase B detector inputterminal of traffic controller LC-ll. For purposes of simplification,normally open switch 39 serves the function of coupling detector memorycircuit E-2 to relay CRV for so long as the phase B right-of-way signalsare displayed by traffic signal circuit 8-1, and contacts 41 serve thefunction of preventing an actuation of sequencer 36 when signals areapplied to phase B detector circuit G-Z. Also, the normally opencontacts CRV-ll of relay CRV are connected between the coil 40 of phaseB sequencer 36 and ground, and the output terminal of the phase Bsequencer 36 is coupled to the phase B signal circuit S-2.

Thus, when a signal is applied by one of the phase A detectors D-2, D-4,through coordination unit C-ll to the phase A detector input terminal oflocal controller LC-l, this signal is stored in detector memory circuitE-2. Upon closure of normally open switch 39, i.e., upon display of aright-of-way signal by the phase B signal circuitry 8-2, the storedsignal energizes relay CRV to thereby actuate the phase B sequencer 36which sequences one step, and in turn, serves to allocate suitable phaseB signal circuitry S-l. Upon allocation of signal circuitry 8-11, theright-of-way interval to phase B is terminated and a phase B clearanceis displayed at phase B, after which phase B is denied right-of-waymovement. As is apparent, actuation of the phase A sequencer 32 is notpossible if phase A traffic detection signals are being applied to thephase A detector circuit G-ll. Similarly, upon application of a signalto the phase B detector input terminal of local controller LC-I, thissignal is stored in phase B detector memory circuit E-ll. Upon closureof normally open switch 35, i.e., upon display of a right-of-way signalby signal circuitry 8-1, the stored signal energizes relay CRT tothereby actuate the phase A sequencer 32 which moves to the next step,and in turn, serves to allocate suitable phase A signal circuitry S-2.Upon allocation of phase A signal circuitry 8-2, the right-of-wayinterval to phase A is terminated and a phase A clearance signal isdisplayed at phase A, after which phase A is denied right-of-waymovement. Similarly, actuation of the phase B sequencer 34 is notpossible for so long as trafiic detection signals are being applied tophase B traffic detector circuit G-2.

COORDINATION UNIT Reference is now made to FIG. 3 which illustrates inmore detail coordination unit C-ll. Coordination unit C-l generallyincludes coordination dials CD-I, CID-2 and CD-3; dial motor selectcontrol circuitry 56; dial n'notor select switching circuitry 50; offsetand synchronization control circuitry 60; synchronization switchingcircuitry 62; background cycle divider circuitry I; phase A coordinationcircuit J; and, phase B coordination circuit It.

Preferably, coordination unit C-l, includes a single timer for timing aparticular background cycle for coordination purposes. The timer, maytake the form of a coordination dial CD-ll, driven by a synchronousmotor MI, being connected across voltage source V for energization. Itis contemplated,

however, that coordination unit C-l, for greater flexibility incoordinating the operation of a full-actuated traffic controller, havethe capability of timing different background cycles. This feature iscommon to coordination units known heretofore for purposes ofcoordinating the operation of pretimed and semiactuated trafiiccontrollers. In order to accomplish this feature, coordination unit C-lalso'includes additional coordination dials CD-2 and CD-3 which arerespectively driven by synchronous motors M2 and M3. Dial motor selectcircuitry 56, dial motor select switching circuitry 58, offset andsynchronization control circuitry 60, and synchronization switchingcircuitry 62 provide the desired selection and control ofsynchronousmotors M1, M2 or M3.

Dial motor select circuitry 58 includes circuit means, such aselectromechanical relay or solid-state switching circuitry, which isineffective to change the operation of motor M1 to one of the othermotors M2 and M3, except during the period that a cam switch I isclosed. Thus, cam switch 1 connected the dial motor select controlcircuitry 56 across voltage source V thereby energizing controlcircuitry 56 only during the time that cam switch 1 is in the closedposition. Further, if coordination dial selector switch DS-2 or switchDS-3, in master controller MC, is closed, circuitry 56 will effectivelyenergize dial motor select switching circuitry 58 to thereby disconnectthe voltage source V from across motor M1 and connect the source Vacross dial select motor M2 if switch DS-2 is closed, or motor M3 ofswitch DS-3 is closed. In addition, coordination unit C-l includesoffset and synchronization control circuitry 60 connected with offsetselector switches -1, 0-2 and 0-3 in master controller MC. Thus,switches 0-1, 0-2 and 0-3 serve when closed, to actuate suitablecircuitry within offset and synchronization control circuitry 60establish different offsets; such as average, inbound preferential, oroutbound preferential. Synchronization switching circuitry 62 includeselectromechanical relays or solid-state control circuitry, and isresponsive to the operation of offset and synchronization controlcircuitry 60 for establishing the offset relationship selected byclosure of one of offset selector switches 0-1, 0-2 or 0-3.

Coordination unit C-l also includes the capability, known in priorcoordination units, for maintaining each local controller in synchronismwith the master controller. This is accomplished with the synchronizingcam wheels l0, l2 and 14 of the master controller, which as previouslydiscussed, each includes an arcuate cutout portion 26 which breaks anenergizing circuit to the offset selector switches 0-1, 0-2 and 0-3 forapproximately 3 percent of the background cycle in effect. Thesynchronizing wheels l0, l2 and 14 are driven at speeds correspondingwith the background cycle in effect. Thus, motor 16 is energized whencoordination dial CD-l is in effect and drive synchronizing wheel at thespeed as dial CD-l driven by motor M1. Similarly, synchronizing wheels12 and 14 are respectively driven at speeds corresponding with thebackground cycles timed by coordination dials CD-2 and CD-3. Power fromthe master controller is normally applied through the offset selectorswitches 0-1, 0-2 and 0-3 for approximately 97 percent of the backgroundcycle. A key, not shown, carried by the coordination dial opens a switchin circuitry 60 for approximately 1 percent of the background cycle. Ifthis interruption occurs during the period that power from the mastercontroller is normally interrupted, i.e., for 3 percent of the cycle, itwill not interrupt operation of motors Ml, M2 or M3, since such anoccurrence is indicative that the local controller is operating insynchronism with the master controller. In the event the interruptionoccurs during the 97 percent period of the background cycle that poweris supplied from the master controller through the offset selectorswitches -l, 0-2 and 0-3, then the synchronization control circuit 60 iseffective to deenergize the motor M1, M2 or M3 in opera tion, to stoprotation of the associated coordination dial. As soon as the 3 percentinterruption in power from the master controller occurs, thesynchronization control circuitry serves to reenergize the selectormotor M1, M2 or M3 so that the switches each having coordination dial ineffect may commence rotation for timing the background cycle insynchronization with the supervising master controller.

In order to simplify the description of the present invention, offsetand synchronization control circuitry 60 is similar to previouscoordination units, such as the coordination unit illustrated anddescribed in the U.S. Pat. to Frank W. Hill, No. 3,196,387 as well asthe offset, split and synchronization features of a system illustratedand described in the U.S. Pat. to Garland E. Fieser and Donald W.Schrepel, No. 3,133,264, both assigned to the same assignee as thepresent invention.

Reference is now made to FIG. 4 which illustrates the phase ofcoordination dial CD-l. Coordination dial CD-l preferably includes acylindrical drum having longitudinal slots extending parallel to theaxis thereof and spaced arcuately around the surface of the drum tothereby define one hundred equally spaced slots. Thus, keys may beplaced in the slots, spaced from each other in percentages, to therebydefine a background cycle. FIG. 4 illustrates one particular arrangementof keys P-1, P-2, P-3, P-9, P-l0, P-ll, P-l5 and G extending radiallyoutward from the surface of coordination dial CD-l.

Reference is now made to FIG. 3, there is schematically illustratedbackground cycle divider circuit I which generally includes a switch SWcomprised of a pair of nonnally open a movable contact 64, 68 and astationary contact 66 and 70. Movable contact 64 is actuated by keys P-lthrough P-IS mounted on coordination dial CD-l. Similarly, movablecontact 68 is actuated by key G also mounted on coordination dial CD-l.Movable contacts 64 and 68 are connected in common with a step switchdriver coil 72 of a step switch 74. Stationary contact 66 is connectedthrough a normally open step switch cam circuit 2 to one terminal ofvoltage supply source V, and stationary contact 70 is connected directlyto that terminal of voltage source V. Step switch 74 includes a rachetmechanism, not illustrated, and a contact-carrying cam shaft, notillustrated, which serve to actuate normally open cam switches 1, 2, 3,4, 8 and 9 in response to energization of driver coil 72 in accordancewith the interval chart illustrated in FIG. 5. Thus, for example, inresponse to actuation of movable contact 68 by key G to engagestationary contact 70, the step switch drive coil 72 is energized,resulting in step switch 74 being actuated such that normally open camswitches 2, 3 and 8 are closed. Cam switch 2 serves to connectstationary contact 66 with one side of voltage source V and ismaintained throughout intervals numbers 1 through 7 by a cam, notillustrated, located on he cam shaft of step switch 74. With normallyopen cam switch 2 closed, upon closure of movable contact 64, a circuitis completed to energize the step switch drive coil 72 thereby movingthe cam shaft to the next position. During the time of interval number8, key G actuates contact 68 to close cam switch 1 thereby allowing dialselect control circuitry 56 to effect a change from coordination dialsCD-l to either coordination dial CD-Z or CD-3, in accordance with theclosure of dial select switch D82 or D83 in master controller MC.

Phase A coordination circuit J includes a normally open cam switch 3coupled between phase A traffic detectors D-2 and D4 and the phase Adetector input terminal of local controller LC-l for, upon closure ofcam switch 3, connecting the phase A traffic detector directly to thephase A detector input terminal of local controller LC-l. Coordinationcircuit J also includes a relay coil CRS having one terminal connectedto phase A traffic detectors D-2 and D4, and the other terminalconnected to one terminal of a normally open cam switch 4. The otherterminal of cam switch 4 is connected to one terminal of the secondarycoil of a step down transformer T1 having its primary coil connectedacross voltage source V. The other output terminal of the secondarywinding of transformer T1 is connected directly to voltage source V. andis also connected through the normally open contacts CRS-l of relay coilCRS to phase A traffic detectors D-2 and D-4. Thus, the circuitryincluding relay coil CR8 and its associated contacts CRS-1 serve as adetector circuit during the period of time normally open cam switch 3 isin the open position. During interval number 2, cam switch 4 will be inthe closed position, and upon detection of traffic by phase detector D-2or D-4, relay coil CRS becomes energized. Upon'energization of relaycoil CBS, normally open relay contact CRS-l will close to therebymaintain relay coil CRS in an energized condition even after a signal isno longer developed by phase A detectors D-2 and -4. During intervalnumber 3, cam switch 3 will again close and the signal developed uponclosure of relay contacts CRS-ll is fed back to phase A detector inputterminal through this cam switch.

Phase B coordination circuit [4 is substantially identical to phase Acoordination circuit J as described above. Coordination circuit itincludes a normally open cam switch 8 coupled between phase B trafficdetectors D-1l and D-3, and the phase B detector input terminal of localcontroller LC-l. Connected between phase B trafiic detectors D-1 and D3and one terminal of the secondary winding of transformer T1 isseriesconnected relay coil CR8 and normally open cam switch 9. Also, thenormally open relay contacts CRB-l of relay coil CRB are connectedbetween the other terminal of the secondary winding of transformer T1and phase B traffic detectors D-1 and 10-3. The circuitry includingrelay coil CRB and its associated contacts CRIB-ll provides a holdingcircuit for information received during the period of time that normallyopen cam switch 3 is in the open position, i.e., during interval number5, and functions in substantially the same manner as the holding circuitincluding relay contacts CRS-ll in the phase A coordination circuit J.

OPERATION Upon energization of master controller MC and coordinationunit C-ll, a selected one of the synchronous motors Ml, M2 and M3 isenergized to drive its associated coordination dial CD4, CD2 or (ID-3.Thus, with dial selector switches D52 and D83 in the open position asillustrated, synchronous motor Ml will be energized to place in effectthe background cycle exhibited by keys P-1 through P- and G oncoordination dial CD-l. Similarly, if dial selector switch DS-2 isclosed, synchronous motor M2 becomes energized to place in effect thebackground cycle exhibited by coordination dial CD-2, and finally, ifdial selector switch DS-2 is moved to the open position and dial switchDS-3 is closed, synchronous motor M3 will become energized. Thus, thedesired background cycle may be placed in effect by altering theposition of coordination dial selector switches DS2 and DS-3 in mastercontroller MC. In addition, one of the offset selector switches 0-1, 0-2or 0-3, associated with the selected motors l6, 13 or in mastercontroller MC, is closed representative of the particular offset ineffect.

Assuming coordination dial CD-l to be in effect, this dial rotates in aclockwise manner as illustrated in FIG. 4 to cyclically time abackground cycle. With reference to FIGS. 3 and 4, it may be seen thatduring each revolution of dial CD-l, key G actuates movable contact 63of switch SW thereby complet ing a circuit for energizing driver coil 72of step switch 74. Upon initial energization of driver coil 72, stepswitch 74 ad vances to interval number ll, during which time camswitches 2, 3 and d are in a closed position. The time duration of thisinterval is determined by the spacing from key G to key P-1, and by thespeed of rotation ofsynchronous motor M1. During this timed interval,signals developed by phase A traffic detectors D-2 and D-4 are applieddirectly to the phase A detector input terminal oflocal controller LC-lthrough cam switch 3. Similarly, during interval number l, signalsdeveloped by phase B traffic detectors D-1 and D3 are applied throughcam switch 3 to the phase B detector input terminal of local controllerLC-ll. Thus, for the duration of interval number ll, local controllerLC-l operates in a manner similar to a twophuse, full-actuated trafficcontroller without external control by a coordination unit. Also, duringinterval number l, normally open cam switch 2 closes so that allactuations of movable contact 64 of switch SW by keys P-ll, P-2, P-3,P-9, lP-lt), lP-ll and P-l5 advance step switch 74 to the next position.

Interval number i is terminated when step switch 74 is advanced to thesecond position by actuation of movable switch contact 64 by key P-ll.Upon termination of interval number ll, cam switch 3 opens and camswitch 4 closes. With cam switch 3 in the open position, signalsdeveloped by the phase A traffic detectors D-2 and D-4 are preventedfrom being applied to the phase A detector input terminals of localcontroller LC-ll. As previously discussed, the circuitry including relaycoil CR5, and its associated relay contacts CRS-ll, provides a detectormemory circuit for storing information representative of a trafficactuation during interval number 2. Accordingly, if traffic is detectedby the phase A traffic detectors D-2 or D-4 during interval number 2,relay contacts CRS-l close and remain closed until cam switch 4 opens.

Upon actuation of movable contact as of switch SW by key -2, step switch74 advances to interval number 3. During interval number 3 as indicatedin FIG. 5, cam switch 3 returns to the closed position thereby againcoupling phase A detectors D-2 and D-4 to the phase A detector inputterminal of local controller LC-ll. If during interval number 2, trafficis detected by either phase A detectors lD-2 or D-4, relay contactsCBS-l will be in a closed position to thereby apply a signal,representative of a traffic detection by phase A detectors D-2 or D-4,through cam switch 3 to the phase A detector input terminal. As may bereadily apparent, the latching circuitry including relay coil CBS andits associated contacts (IRS-l may be eliminated from the circuit ifpresence type detectors are substituted for spot detectors D-2 and M ofthe referred embodiment. in such a case, the presence detectors, onceactuated by traffic, remain actuated so long as traffic remains withinthat phase; therefore, during interval number 3, if traffic remains inphase A, a signal representative of the traffic will be applied to thephase A detector input terminal of local controller LC-l at thecommencement ofinterval number 3.

Upon actuation of movable contact 64 of switch SW by key P3, step switch74 advances to interval number 4. During interval number 4, as duringinterval number ll, cam switches 2, 3 and B are in the closed position.In addition, cam switch 4, being closed prior to interval number 4,opens to thereby reset the latching circuit including relay coil CR5 andits associated contact CRS-ll. Also, during interval number 4, localcontroller LC-ll functions as a conventional two-phase, full-actuatedtraffic controller having no external control by a coordination unit.

During interval number 5, i.e., upon actuation of movable contact 64 ofswitch SW by key lP--9, normally open cam switch 3 opens and cam switch9 closes. Cam switches 3 and 9 provide functions, with respect to thephase B detectors D-l and D-3, are analogous to the functions providedby cam switches 3 and 4, respectively. Accordingly, during intervalnumber 5, the contacts of cam switch 8, being in an open position,prevent signals developed by phase B traffic detectors 13-11, and D-3from being applied to the phase B detector input terminal of localcontroller LC-ll. In addition, the latching circuit, including relaycoil CRB and its associated contact CRB-l, provides memory retention oftraffic detected during interval number 3.

Upon commencement of interval number 6, i.e., upon actuation of movablecontact 64 of switch SW by key P-1l0, cam switch 8 again closes therebyagain coupling the phase B detectors D-ll and D-3 to the phase Bdetector input terminal of local controller LC-ll. As before, if relaycontact CRB-l is in a closed position, resulting from a trafficdetection by detectors D-l or 13-13 during interval number 5, a signalis applied through contacts CRBJ, and cam contact 3, to the phase Bdetector input terminal of local controller lLC-ll.

Upon actuation of movable contact 64 by key P-ll, step switch 74 isadvanced to interval number 7, and as during intervals l and 4, camswitches 2, 3 and 8 remain in the closed position. in addition, camswitch 9, being closed during intervals number and 6, opens to therebyreset the latching circuit including relay coil CR8 and its associatedcontacts CRB-l. A resynchronizing interval, or interval number 8, occurswhen key P- actuates movable contact 64 of switch SW, which in turncauses cam switch 1 to close thereby energizing dial motor selectcircuitry 56. Only during the period of time that motor select controlcircuitry 56 is energized, will coordination dial select switches DS-2and DS-3 be effective to disconnect motor Ml from across voltage sourceV, and connect one of the other motors M2 or M3 across the voltagesource V.

From the foregoing description of operation it is apparent thatcoordination unit C-l serves to provide four primary functions, to wit,the coupling and decoupling of phase A traffic detectors D-2 and D4 fromthe phase A detection input terminal, and the coupling and decoupling ofphase B traffic detectors D-1 and D3 from the phase B detection inputterminal of local controller LC-l at predetermined times during thecoordinated background cycle.

Accordingly, upon detection of traffic by either of the phase Adetectors D-2, D-4, a signal is applied through coordination unit C-l tothe phase A detector circuit E-2, assuming the coordination unit C-l isin any interval of operation other than interval number 2. If, however,coordination unit C-l is in interval number 2 when traffic is detectedby either of the phase A traffic detectors D-2, D-4, the detector memorycircuit including relay coil CR8 and its associated contacts CRS-lretain an indication of traffic detection during interval number 2 andapplies a signal to the phase A detector memory circuit E-2 duringinterval number 3. Similarly, upon detection of traffic by either of thephase B traffic detectors D-l, D-3, a signal is applied throughcoordination unit 6-1 to the phase B detector memory circuit D-l,assuming the coordination unit C-] is in any interval of operation otherthan interval number 5, If, however, coordination unit C-l is ininterval number 5 when traffic is detected by either of the phase Btraffic detectors D-l, D-3, the detector memory circuit including relaycoil CR5 and its associated contacts CRB-l retains an indication oftraffic detection during interval number 5 and applies a signalrepresentative of this detection to the phase B detector memory circuitE-l during interval number 6.

Thus, assuming a phase B right-of-way signal is exhibited by localcontroller LC-l, i.e., assuming normally open switch 39 is in the closedposition, assuming no traffic is being detected by traffic detectorsD-l, D-3, i.e., contacts 41 are in a closed position and assuming thecoordination unit is in any interval of operation other than intervalnumber 2, upon detection of traffic by either of the phase A trafficdetectors D-2, D-4, a signal is applied through the phase A detectormemory circuit E-2, switch 39 to thereby energize relay CRV. Uponenergization of relay CRV, the coil 40 of phase B sequencer 36 isenergized to thereby actuate sequencer 36 to the next position. Whensequencer 36 is actuated to the next position, this circuit serves toactuate suitable phase B signal circuitry 8-1, for purposes ofterminating allocation of a right-of-way interval to phase B andcommence timing a phase B clearance interval, after which phase B deniedright-of-way movement.

In a similar manner to that discussed with respect to the circuitryassociated with phase B, assuming a phase A right-ofway signal isexhibited by local controller LC-l, i.e., normally open switch 35 is inthe closed position, assuming no traffic is being detected by the phaseA traffic detectors D-2, D4, i.e., contacts 37 are in the closedposition, and assuming the coordination unit is in any interval ofoperation other than interval number 5, upon detection of traffic by thephase B traffic detectors D-l, D-3, a signal is applied through detectormemory circuit E-l, switch 35, to thereby energize relay CRT. Uponenergization of relay CRT, a signal is applied to the coil 38 of phase Asequencer 32 to thereby actuate sequencer 32 to the next position. Whensequencer 32 is actuated to the next position, this circuit serves toactuate suitable phase A signal circuitry 8-1 for purposes ofterminating allocation of a right-ofway interval to phase A and commencetiming a phase A clearance interval to phase A, after which phase isdenied right-of-way movement.

Assuming that a phase B right-of-way signal is exhibited by localcontroller LC-1, and traffic is present in phase B, rightof-way signalswill remain in phase B until either traffic is no longer detected inphase B or the phase B detectors D-l, 0-3, are decoupled from the phaseB detection circuit 6-2 by coordination unit C-l. Thus, assuming a phaseB right-of-way signal is exhibited by local controller LC-l, andassuming a continuous flow of traffic in phase B, right-of-way willremain in phase B until interval number 5 of coordination unit C-lcommences, at which time the signals developed by the phase B trafficdetectors D-l, D-3 are no longer applied to the phase B detectioncircuit G-2. Upon removal of these signals from the phase B detectorcircuit G-2, contacts 41 close, and as previously discussed, trafficactuations in phase A cause a transfer of right-of-way from phase B tophase A. Thus, if at interval number 5, traffic is present in phase A,right-ofway signals will immediately be transferred to phase Airrespective of the presence of traffic in phase B. Similarly, assuminga phase A right-of-way signal is exhibited by local controller LC-l, andthat a continuous flow of traffic exists in phase A, right-of-waysignals will remain in phase A until the commencement of interval number2, at which time the phase A traffic detectors D-2, D-4, will becomedecoupled from the phase A circuitry, thereby allowing right-of-waytransfer to phase B, assuming traffic detection by the phase B detectorsD-l, D-3, irrespective of the presence of traffic in phase A.

Accordingly, when coordination unit C-l commences interval number 3,signals developed by the phase A detectors D-2, D-4, are removed fromthe local controller LC-l. If at this time, there is a detection byeither of the phase B detectors D-l, D-3, right-of-way will beimmediately transferred from phase A to phase B. So as to remembertraffic detection in phase A during interval number 2, normally open camswitch 4 is closed so as to retain an indication of traffic detectionduring interval number 2. During interval number 3, this information isfed back into local controller LC-l through cam switch 3.

Thus, there is provided a method of coordinating the operation of afull-actuated traffic controller LC-l which controls allocations of go,caution and stop intervals to at least two traffic phases, phase A andphase B, each having traffic detector means D-l, D-2, D-3 and D-4associated therewith for detecting traffic and developing a signal inresponse to the detection of traffic, the controller LC-l including gointerval actuation means associated with each phase for commencing a gointerval display. The method comprises the steps of: timing a backgroundcycle having a predetermined time duration; dividing the backgroundcycle into at least two timed intervals respectively associated witheach phase controlled by the controller LC-l, during one of theintervals, electrically coupling one of the traffic detector means D-2,D4 to an associated one of the go interval actuating means R-l;commencing a go interval display with the go interval actuating meansR-l; electrically decoupling that traffic detector means D-2, D-4 fromthe associated go interval actuating means R-l; and, terminating the gointerval display with the go interval actuating means R-l at apredetermined period of time after the traffic detector means D-2, D-4is electrically decoupled from the associated go interval actuatingmeans R-l.

Whereas the background cycle timer has been described as taking the formof a synchronous motors within a coordination unit C-l, driven bycorresponding synchronous motors within a master controller MC, theinvention contemplates that other forms of timers may be used which havethe capability of actuating circuitry during selected times, i.e., timeperiods analogous to keys G and P-l through P-lS of coordination dialCD-l. Similarly, whereas the invention has been described in conjunctionwith electromechanical circuitry such as dial keys and movable contactsof a step switch, the invention contemplates that this circuitry may bereplaced-with suitable solid-state switching circuitry.

Although the invention has been shown and described with a preferredembodiment, it will be readily apparent to those skilled in the art thatvarious changes in form and arrangement of parts may be made to suitrequirements without departing from the spirit and the scope of theinvention.

lclaim:

1. A coordination unit for coordinating the operation of a full-actuatedtraffic controller in an interconnected signalized system, saidcontroller serving to control a traffic signal which displays go,caution and stop signals for at least two traffic phases each havingassociated therewith traffic detector means for detecting traffic intheir respective phase and developing a go termination control signalfor one phase in response to the detection of traffic in another phase,said controller having control circuit means, each associated with oneof said phases; each said control circuit means including go intervalterminating means for, upon receipt of a said control signal by thecontrol circuit means associated with a second phase, terminating thedisplay of said go signal for a first phase; said coordination unitcomprising:

background-cycle means for cyclically timing successive backgroundcycles, each having a predetermined time duration;

means for dividing each said background cycle into at least two timedbackground intervals respectively associated with each of said phases;actuatable means responsive during one of said associated backgroundintervals for directly connecting one of said traffic detector means toan associated one of said control circuit means for the duration of saidone associated background interval so that a said traffic detectionresponsive control signal developed by said one traffic detector meansis applied to said one control circuit means only during said oneassociated background interval; and,

actuatable means responsive during another of the said associatedbackground intervals for directly connecting the other said trafficdetector means to the other associated one of said control circuit meansso that a said traffic detection responsive control signal developed bythe other traffic detector means is applied to the other control circuitmeans only during said other associated background interval.

2. A coordination unit as set forth in claim 1 wherein said dividingmeans divides said background cycle so as to include for each phase asecond background interval which commences substantially upontermination of said first background interval; and,

said coordination unit includes for each phase, actuatable memory meansfor storing a said go interval termination signal during an associatedsaid second background interval, said acutatable memory means having aninput circuit means for receiving a said go interval termination signalduring an associated said second background interval and an outputcircuit means for applying said stored signal to an associated controlcircuit means upon termination of an associated said second backgroundinterval.

3. A coordination unit as set forth in claim 1 wherein each saidactuatable means includes actuatable control means having a first andsecond condition, said control circuit means being coupled to saidbackground-cycle timing means for actuating each said control circuitmeans to said first condition during the associated said backgroundinterval and to said second condition during the remainder of theassociated said background interval so that said signals developed bysaid traffic detector means are applied to said control circuit meansonly during the associated background intervals.

A. A coordination unit as set forth in claim 3 wherein each saidactuatable control means is connected directly between the associatedsaid traffic detector means and the associated said control circuitmeans.

5. A coordination unit as set forth in claim l wherein said dividingmeans is adjustable for adjustably dividing said background cycle intotimed background intervals of desired timed durations.

6. A coordination unit as set forth in claim 5 wherein saidbackground-cycle timing means includes a motor driven coordination dialand wherein said dividing means includes a plurality of switch actuatorkeys carried by said dial at preselected angularly spaced locations onsaid dial.

7. A coordination unit as set forth in claim 2 wherein each saidactuatable memory means includes an actuatable control means, for uponenergization, storing a said go termination control signal; and switchmeans associated with each said actuatable control means for couplingeach said actuatable control means to a voltage supply source during anassociated said second background interval; and said traffic detectormeans, upon detection of traffic, coupling said actuatable control meansto another source of potential so that said actuatable control means isenergized during said second background interval upon detection oftraffic by said traffic detector means.

8. A coordination unit for coordinating the operation of a full-actuatedtraffic controller in an interconnected signalized system, saidcontroller serving to control a traffic signal which displays go,caution and stop signals for at least two traffic phases each havingassociated therewith traffic detector means for detecting traffic intheir respective phase and developing a go interval initiation controlsignal for any phase in response to the detection of trafiic in suchphase, said controller having phase detector input circuit means, eachassociated with one of said phases for, upon receipt of a said gointerval initiation control signal associated with a phase developing asignal for commencing the display of said go signal for the associatedphase; said coordination unit comprising:

background cycle means for cyclically timing successive backgroundintervals each having a predetermined time duration;

means for dividing each said background cycle into at least two timebackground intervals respectively associated with each of said phases;

actuatable means responsive during one of said associated backgroundintervals for coupling one of said traffic detector means to anassociated one of said phase detector input circuit means for theduration of said one associated interval so that a said go intervalinitiation control signal developed by said one traffic detector meansis applied to said one phase detector input circuit means only duringsaid one associated background interval; and,

actuatable means responsive during the other said associated intervalfor coupling the other said traffic detector means to the otherassociated one of said phase detector input circuit means so that a saidgo interval initiation control signal developed by the other trafficdetector means is applied to the other phase detector input circuitmeans only during said other associated background interval.

9. A coordination unit as set forth in claim 8 wherein said dividingmeans divides said background cycle so as to include for each phase asecond background interval which commences substantially upontermination of said first interval; and,

said coordination unit includes for each phase, actuatable memory meansfor storing a said control signal during an associated said secondbackground interval, said actuatable memory means having an inputcircuit means for receiving a said control signal during an associatedsaid second background interval and an output circuit means for applyingsaid stored signal to an associated control circuit means upontermination of an associated said second background interval.

110. A method of coordinating the operation of a full-actuated trafficcontroller which controls allocations of go, caution, and stop intervalsfor at least two traffic phases, each having traffic detector meansassociated therewith for detecting traffic and developing a signal inresponse to the detection of traffic, said controller including gointerval actuation means associated with each phase for commencingdisplay of a go interval signal;

said method of coordination comprising the steps of: timing a backgroundcycle having a predetermined time duration; dividing said backgroundcycle into at least two timed background intervals respectivelyassociated with each said phase controlled by said controller;electrically coupling one of said traffic detector means directly to oneof said go interval actuating means during one of said backgroundintervals; commencing display of a go interval signal with said one gointerval actuating means; electrically decoupling said one trafficdetector means from said one go interval actuating means; and,terminating display of said go interval signal with said go intervalactuating means at a predetermined period of time after said one trafficdetector means is electrically decoupled from said one go intervalactuating means.

11. A method of coordinating the operation of a full-actuated trafficcontroller as set forth in claim 10 including the additional steps of:

electrically coupling the other of said traffic detector means directlyto the other said go interval actuating means; commencing display of asecond go interval signal with said other go interval actuating means;

electrically decoupling said other traffic detector means from saidother go interval actuating means; and terminating said display of asecond go interval signal with said other background interval actuatingmeans at a predetermined period of time after said other trafficdetector means is electrically decoupled from said other go intervalactuating means.

F I! i t i

1. A coordination unit for coordinating the operation of a fullactuatedtraffic controller in an interconnected signalized system, saidcontroller serving to control a traffic signal which displays go,caution and stop signals for at least two traffic phases each havingassociated therewith traffic detector means for detecting traffic intheir respective phase and developing a go termination control signalfor one phase in response to the detection of traffic in another phase,said controller having control circuit means, each associated with oneof said phases; each said control circuit means including go intervalterminating means for, upon receipt of a said control signal by thecontrol circuit means associated with a second phase, terminating thedisplay of said go signal for a first phase; said coordination unitcomprising: background-cycle means for cyclically timing successivebackground cycles, each having a predetermined time duration; means fordividing each said background cycle into at least two timed backgroundintervals respectively associated with each of said phases; actuatablemeans responsive during one of said associated background intervals fordirectly connecting one of said traffic detector means to an associatedone of said control circuit means for the duration of said oneassociated background interval so that a said traffic detectionresponsive control signal developed by said one traffic detector meansis applied to said one control circuit means only during said oneassociated background interval; and, actuatable means responsive duringanother of the said associated background intervals for directlyconnecting the other said traffic detector means to the other associatedone of said control circuit means so that a said traffic detectionresponsive control signal developed by the other traffic detector meansis applied to the other control circuit means only during said otherassociated background interval.
 2. A coordination unit as set forth inclaim 1 wherein said dividing means divides said background cycle so asto include for each phase a second background interval which commencessubstantially upon termination of said first background interval; and,said coordination unit includes for each phase, actuatable memory meansfor storing a said go interval termination signal during an associatedsaid second background interval, said acutatable memory means having aninput circuit means for receiving a said go interval termination signalduring an associated said second background interval and an outputcircuit means for applying said stored signal to an associated controlcircuit means upon termination of an associated said second backgroundinterval.
 3. A coordination unit as set forth in claim 1 wherein eachsaid actuatable means includes actuatable control means having a firstand second condition, said control circuit means being coupled to saidbackground-cycle timing means for actuating each said control circuitmeans to said first condition during the associated said backgroundinterval and to said second condition during the remainder of theassociated said background interval so that said signals developed bysaid traffic detector means are applied to said control circuit meansonly during the associated background intervals.
 4. A coordination unitas set forth in claim 3 wherein each said actuatable control means isconnected directly between the associated said traffic detector meansand the associated said control circuit means.
 5. A coordination unit asset forth in claim 4 wherein said dividing means is adjustable foradjustably dividing said background cycle into timed backgroundintervals of desired timed durations.
 6. A coordination unit as setforth in claim 5 wherein said background-cycle timing means includes amotor driven coordination dial and wherein said dividing means includesa plurality of switch actuator keys carried by said dial at preselectedangularly spaced locations on said dial.
 7. A coordination unit as setforth in claim 2 wherein each said actuatable memory means includes anactuatable control means, for upon energization, storing a said gotermination control signal; and swiTch means associated with each saidactuatable control means for coupling each said actuatable control meansto a voltage supply source during an associated said second backgroundinterval; and said traffic detector means, upon detection of traffic,coupling said actuatable control means to another source of potential sothat said actuatable control means is energized during said secondbackground interval upon detection of traffic by said traffic detectormeans.
 8. A coordination unit for coordinating the operation of afull-actuated traffic controller in an interconnected signalized system,said controller serving to control a traffic signal which displays go,caution and stop signals for at least two traffic phases each havingassociated therewith traffic detector means for detecting traffic intheir respective phase and developing a go interval initiation controlsignal for any phase in response to the detection of traffic in suchphase, said controller having phase detector input circuit means, eachassociated with one of said phases for, upon receipt of a said gointerval initiation control signal associated with a phase developing asignal for commencing the display of said go signal for the associatedphase; said coordination unit comprising: background cycle means forcyclically timing successive background intervals each having apredetermined time duration; means for dividing each said backgroundcycle into at least two time background intervals respectivelyassociated with each of said phases; actuatable means responsive duringone of said associated background intervals for coupling one of saidtraffic detector means to an associated one of said phase detector inputcircuit means for the duration of said one associated interval so that asaid go interval initiation control signal developed by said one trafficdetector means is applied to said one phase detector input circuit meansonly during said one associated background interval; and, actuatablemeans responsive during the other said associated interval for couplingthe other said traffic detector means to the other associated one ofsaid phase detector input circuit means so that a said go intervalinitiation control signal developed by the other traffic detector meansis applied to the other phase detector input circuit means only duringsaid other associated background interval.
 9. A coordination unit as setforth in claim 8 wherein said dividing means divides said backgroundcycle so as to include for each phase a second background interval whichcommences substantially upon termination of said first interval; and,said coordination unit includes for each phase, actuatable memory meansfor storing a said control signal during an associated said secondbackground interval, said actuatable memory means having an inputcircuit means for receiving a said control signal during an associatedsaid second background interval and an output circuit means for applyingsaid stored signal to an associated control circuit means upontermination of an associated said second background interval.
 10. Amethod of coordinating the operation of a full-actuated trafficcontroller which controls allocations of go, caution, and stop intervalsfor at least two traffic phases, each having traffic detector meansassociated therewith for detecting traffic and developing a signal inresponse to the detection of traffic, said controller including gointerval actuation means associated with each phase for commencingdisplay of a go interval signal; said method of coordination comprisingthe steps of: timing a background cycle having a predetermined timeduration; dividing said background cycle into at least two timedbackground intervals respectively associated with each said phasecontrolled by said controller; electrically coupling one of said trafficdetector means directly to one of said go interval actuating meansduring one of said background intervals; commencing display of a gointerval signal with said one go interval actuating means; electricallydecoupling said one traffic detector means from said one go intervalactuating means; and, terminating display of said go interval signalwith said go interval actuating means at a predetermined period of timeafter said one traffic detector means is electrically decoupled fromsaid one go interval actuating means.
 11. A method of coordinating theoperation of a full-actuated traffic controller as set forth in claim 10including the additional steps of: electrically coupling the other ofsaid traffic detector means directly to the other said go intervalactuating means; commencing display of a second go interval signal withsaid other go interval actuating means; electrically decoupling saidother traffic detector means from said other go interval actuatingmeans; and terminating said display of a second go interval signal withsaid other background interval actuating means at a predetermined periodof time after said other traffic detector means is electricallydecoupled from said other go interval actuating means.